Urban Mobility

A Rescuer for Our Cities

A prototype for the streetcars of tomorrow: In cooperation with Stadtwerke Ulm (SWU), Siemens has begun to turn its vision of self-driving streetcars into reality. Since 2015, the company has been working on the first stage of this process: a driver assistance system designed to prevent collisions.

In the mid-20th century streetcars were regarded as no longer up to date, but today they are once again booming. They are reducing traffic volumes and air pollution all over the world, thus enhancing the attractiveness of many cities. However, if streetcars are to continue to thrive, they need to evolve: They must become intelligent. Siemens has already developed the first smart streetcar to the point of readiness for large-scale production.

No matter how different major cities are from one another, they all have one thing in common: During rush hours their streets are congested, people are stuck in traffic, and the many combustion engines produce high levels of emissions. That’s why experts around the world believe that one of the oldest means of transportation — the streetcar — could play a key role in reducing these problems.

The main reasons are obvious. Streetcars travel on rails and thus don’t get stuck in traffic jams. Moreover, they have a much larger transport capacity than automobiles. A streetcar can carry between 200 and 600 passengers. As a result, a fully occupied streetcar can on average replace more than 150 cars. According to Dresdner Verkehrsbetriebe AG, the municipal transport company of the city of Dresden in Germany, moving one person on a streetcar produces up to 90 percent less carbon dioxide than the same person driving a car. There is also a “rail bonus”: People regard streetcars as a reliable means of transportation.

Competing with Self-driving Cars and Buses

But in spite of these advantages, streetcars are in danger of once again losing their appeal in the near future, especially compared to passenger cars. The reason is the advent of self-driving vehicles. “Self-driving vehicles will enable people who couldn’t previously drive, such as children and the elderly, to travel in automobiles,” says Matthias Hofmann, product manager for streetcars at Siemens Mobility. However, this expert adds that self-driving vehicles would not be a good alternative for our cities, where too many low-occupancy vehicles are already filling the streets. “This means that streetcars will also have to become driverless,” says Hofmann. “They might also operate as small, flexible units. This would help to attract more passengers and keep people from driving. All of these factors would also make streetcars an environmentally friendly public transportation system that perfectly closes the gap between buses for distribution and feeder routes, on the one hand, and subways and commuter trains as mass transit systems, on the other.”

The Challenges of an Open System

“We’re working on the smart streetcar of the future,” says Christian Klier about the work being done by the development team at Siemens Mobility in Berlin-Adlershof. The team consists of robotics specialists, software developers, and image processing experts. Klier is responsible for the project’s technical implementation. In cooperation with automotive suppliers, universities, startups, and customers, the team is creating a smart sensor-software platform designed to offer assisted and autonomous driving for all of Siemens’ rail vehicles.

Unlike subway trains, which operate in specially secured infrastructures that form a closed system, autonomous streetcars will move in an open system along with many other road users, such as cars, cyclists, and pedestrians. “That’s why most of the intelligence needed to operate them will have to be onboard,” says Klier. Streetcars will thus need to be equipped with sensors to monitor their surroundings, evaluate data, and make decisions. A streetcar will, for example, have to decide whether it can continue on its route, how fast it can travel, and whether there is any risk of a collision. What’s more, streetcars will need to be connected to other road users and to a control center, and they will have to interact with people and vehicles, just as tram drivers do today.

In cooperation with the utility serving the German city of Ulm, Siemens has begun to turn its vision of self-driving streetcars into reality.

The First Assistance Solution Is Ready for Series Production — the Siemens Tram Assistant Is Up and Running

In cooperation with Stadtwerke Ulm (SWU), a utility serving the German city of Ulm, Siemens has begun to turn its vision of self-driving streetcars into reality. Since 2015, the company has been working on the first stage of this process: a driver assistance system designed to prevent collisions. It consists of sensors that are also used in cars. A system consisting of radar and a camera helps the driver to avoid collisions with other streetcars, cars, buses, and trucks by means of warning signals or automatic braking. SWU is providing a vehicle and personnel for test drives and also for the system’s use during regular operation. It is also contributing its operational know-how in order to optimally adapt the system to the special operating conditions of streetcars. Today, two years later, the driver assistance system is ready for series production — it’s the first step toward the self-driving streetcar. All of the streetcars in Ulm, as well as in The Hague and Bremen, will be fitted with the Siemens Tram Assistant V1.0. “There’s significant demand for accident-prevention systems adapted for use in streetcars, because such systems reduce costs and increase vehicle availability,” says Matthias Hofmann, who works closely with a number of public transport operators.

For example, a streetcar has to decide whether it can continue on its route, how fast it can travel, and whether there is any risk of a collision. The system monitors its surroundings by means of sensors, evaluates the data it receives, and then makes a decision. The streetcar has to interact with people and vehicles, just as tram drivers do today.

The customers have a long list of wishes that they want Siemens to fulfill. For instance, they are looking for improved system reliability, speed monitoring, and more precise recognition of potential collision objects such as pedestrians and cyclists. “We are gradually developing the modules that are needed for the final stage of such systems — the self-driving streetcar,” says Holger Last, who heads Siemens’ Assisted and Automated Driving for Rail program.

Endurance Testing of the Pilot Streetcar

The Ulm test tram also contains a development and evaluation system that was designed by Siemens in order to prepare the vehicle for autonomous driving. The system includes high-performance sensors from the automotive and industrial sectors, such as laser scanners, special radars, and cameras — sensors that are still expensive today. The system uses them to comprehensively monitor what’s going on in front of and alongside the streetcar and to evaluate the resulting information with the help of smart algorithms that Siemens developed in cooperation with its partners. The system also registers all of the vehicle’s responses, such as (emergency) braking, slow progress, and long stops en route, and compares them with the sensor results. The data is stored on a hard disk and transmitted by radio to Siemens’ Berlin lab, where it is fed into the development systems. After being tested in a virtual environment, new software versions can thus be quickly tried out in real life and qualified for productive use.

“The Assisted and Automated Driving for Rail program isn’t only about autonomous streetcars,” says Holger Last. “We’re also using our sensor and development platform to create solutions for the automation of shunting and freight traffic as well as for regional and long-distance transportation. To this end, we are using the experiences and the software that we develop for streetcars. However, we’re also facing new challenges, such as the creation of a reliable obstacle-and-signal recognition system, which has to extend outward at least 1,000 meters because of the high speeds that streetcars reach in open stretches.”

In the Future, All the Knowledge Will Be in the Vehicle

In the future, Siemens’ self-driving rail vehicle system will combine onboard sensors and automation technology with information from infrastructures such as railroad crossings, from other vehicles, such as their direction of travel, and from track-side systems, such as operational control centers and interlockings. “Siemens can supply highly integrated solutions for these problems, because we have complete access to the wealth of data from our systems,” says Last.